Britain on Wednesday urged the release of "all political prisoners" in the Maldives following the jailing of Islamist leader Sheikh Imran Abdulla.

Junior foreign minister Hugo Swire said Imran's conviction on terrorism charges "raises worrying questions about freedom of speech, the rule of law and the government's commitment to democracy."

Maldives on Tuesday sentenced Imran, the leader of the country's main Islamist party, to 12 years in jail.

The opposition Adhaalath Party (AP) leader was charged under a 1990 anti-terrorism law for allegedly inciting unrest during an anti-government rally last May on the capital island Male. His imprisonment comes 11 months after the highly controversial jailing of the country's main opposition leader Mohamed Nasheed, who last month obtained prison leave to undergo urgent surgery in London.

Swire said that Tuesday's conviction was a "backward step" after the granting of Nasheed's medical leave and called for further action. "I urge the government to work towards greater judicial independence and to restore confidence in democracy," he said in a statement on the government's website.